public class TableFrameInfo : MapSurroundInfo 

//Create a new table frame on the active layout.

Layout layout = LayoutView.Active.Layout;

//Perform on the worker thread
await QueuedTask.Run(() =>
{
  //Build 2D envelope geometry
  Coordinate2D rec_ll = new Coordinate2D(1.0, 3.5);
  Coordinate2D rec_ur = new Coordinate2D(7.5, 4.5);
  //At 2.x - Envelope rec_env = EnvelopeBuilder.CreateEnvelope(rec_ll, rec_ur);
  Envelope rec_env = EnvelopeBuilderEx.CreateEnvelope(rec_ll, rec_ur);

  //Reference map frame
  MapFrame mf = layout.FindElement("Map Frame") as MapFrame;

  //Reference layer
  Map m = mf.Map;
  FeatureLayer lyr = m.FindLayers("GreatLakes").First() as FeatureLayer;

  //Build fields list
  var fields = new[] { "NAME", "Shape_Area", "Shape_Length" };

  //Construct the table frame
  //At 2.x - TableFrame tabFrame = LayoutElementFactory.Instance.CreateTableFrame(layout, rec_env, mf, lyr, fields);
  var surroundInfo = new TableFrameInfo()
  {
    FieldNames = fields,
    MapFrameName = mf.Name,
    MapMemberUri = lyr.URI
  };
  var tabFrame = ElementFactory.Instance.CreateMapSurroundElement(layout, rec_env, surroundInfo) as TableFrame;
});

//Create a table frame.

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //Build 2D envelope geometry
  Coordinate2D rec_ll = new Coordinate2D(1.0, 3.5);
  Coordinate2D rec_ur = new Coordinate2D(7.5, 4.5);
  //At 2.x - Envelope rec_env = EnvelopeBuilder.CreateEnvelope(rec_ll, rec_ur);
  Envelope rec_env = EnvelopeBuilderEx.CreateEnvelope(rec_ll, rec_ur);

  //Reference map frame and layer
  MapFrame mf = layout.FindElement("Map Frame") as MapFrame;
  FeatureLayer lyr = mf.Map.FindLayers("GreatLakes").First() as FeatureLayer;

  //Build fields list
  var fields = new[] { "NAME", "Shape_Area", "Shape_Length" };

  //Construct the table frame
  //At 2.x - TableFrame tabFrame = LayoutElementFactory.Instance.CreateTableFrame(
  //              layout, rec_env, mf, lyr, fields);

  var tableFrameInfo = new TableFrameInfo()
  {
    FieldNames = fields,
    MapFrameName = mf.Name,
    MapMemberUri = lyr.URI
  };
  var tabFrame = ElementFactory.Instance.CreateMapSurroundElement(
    layout, rec_env, tableFrameInfo) as TableFrame;
});

//Must be on QueuedTask.Run(() => { ...

//Build geometry
Coordinate2D ll = new Coordinate2D(1, 1);
Coordinate2D ur = new Coordinate2D(4, 4);
Envelope env = EnvelopeBuilderEx.CreateEnvelope(ll, ur);

var tableFrameInfo = new TableFrameInfo()
{
  MapFrameName = mapFrameName,
  MapMemberUri = uri
};
var attribs = new List<CIMStringMap>();
for (int i = 1; i < 6; i++)
{
  attribs.Add(new CIMStringMap
  {
    Key = $"Key {i}",
    Value = $"Value {i}"
  });
}
var elemInfo = new ElementInfo()
{
  CustomProperties = attribs
};
var tableFrameElem = ElementFactory.Instance.CreateMapSurroundElement(
                              layout, env.Center, tableFrameInfo,
                              "New Table Frame", false, elemInfo) as TableFrame;